Does montelukast (Singulair) affect iron absorption?

Montelukast Does Not Affect Iron Absorption

Montelukast (Singulair) does not affect iron absorption based on available evidence and guidelines. There is no documented interaction between montelukast and iron metabolism in any of the clinical guidelines or research literature.

Mechanism of Action and Pharmacology

Montelukast is a selective leukotriene receptor antagonist (LTRA) that specifically targets the cysteinyl leukotriene receptor 1 (CysLT1) 1. It is primarily used for:

• Treatment of asthma in adults and children as young as 2 years old 2, 3
• Management of allergic rhinitis 2

The medication works by blocking leukotrienes, which are inflammatory mediators, rather than affecting gastrointestinal processes related to nutrient absorption.

Iron Absorption Factors

Iron absorption is primarily regulated by:

1. Gastrointestinal acidity: Gastric acid promotes the absorption of non-heme iron 4
2. Iron stores in the body: The gastrointestinal tract increases iron absorption when body stores are low 2
3. Dietary composition: Factors affecting iron bioavailability include:
   • Heme vs. non-heme iron sources (heme iron is 2-3 times more absorbable) 2
   • Enhancers: Vitamin C, meat proteins 2
   • Inhibitors: Polyphenols, tannins, phytates, calcium 2

Evidence on Montelukast and Iron Metabolism

The comprehensive guidelines on iron management 5 and iron deficiency 2 do not list montelukast among medications that affect iron absorption. Similarly, the montelukast guidelines and drug information 2 do not mention any impact on iron metabolism or absorption.

Medications known to affect iron absorption include:

• Proton pump inhibitors and H2 blockers (by reducing gastric acidity) 4
• Calcium carbonate (direct inhibition of iron absorption) 4

Clinical Implications

For patients taking montelukast:

• No special considerations are needed regarding timing of iron supplements
• No dose adjustments of iron supplements are required
• No additional monitoring of iron status is necessary beyond what would be standard for the patient's condition

Potential Considerations

While montelukast itself doesn't affect iron absorption, it's worth noting that:

1. The underlying conditions treated with montelukast (asthma, allergic rhinitis) are not known to affect iron absorption
2. Montelukast has been studied for potential hepatoprotective effects 1, but these do not relate to iron metabolism
3. The primary concerns with montelukast relate to potential neuropsychiatric adverse events rather than nutritional interactions 6

Conclusion

Healthcare providers can confidently prescribe montelukast without concerns about its impact on iron absorption or metabolism. Patients requiring both montelukast and iron supplementation do not need special scheduling or dosing adjustments related to this combination.